The normal range for blood oxygen levels is between 75 and 100 millimeters of mercury (mm Hg) . However, the normal range may vary depending on factors such as lung disease, high altitude, and other medical conditions. If blood oxygen saturation levels fall to 88% or lower, it is recommended to seek immediate medical attention. If youre using an oximeter at home and your oxygen saturation level is 92% or lower, call your healthcare provider. It is important to note that pulse oximeters are not always accurate, and a more accurate result can be obtained through a blood test.